scholarly journals Coordinated control of the type IV pili and c‐di‐GMP‐dependent antifungal antibiotic production in L ysobacter by the response regulator PilR

2021 ◽  
Vol 22 (5) ◽  
pp. 602-617
Author(s):  
Kangwen Xu ◽  
Danyu Shen ◽  
Nianda Yang ◽  
Shan‐Ho Chou ◽  
Mark Gomelsky ◽  
...  
Keyword(s):  
Response Regulator ◽  
Antibiotic Production ◽  
Coordinated Control ◽  
Type Iv Pili ◽  
Antifungal Antibiotic ◽  
Type Iv

scholarly journals Lysobacter PilR, the Regulator of Type IV Pilus Synthesis, Controls Antifungal Antibiotic Production via a Cyclic di-GMP Pathway

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Yuan Chen ◽  
Jing Xia ◽  
Zhenhe Su ◽  
Gaoge Xu ◽  
Mark Gomelsky ◽  
...  
Keyword(s):  
Response Regulator ◽  
Antibiotic Production ◽  
Second Messenger ◽  
Twitching Motility ◽  
Type Iv Pilus ◽  
Content Type ◽  
Lysobacter Enzymogenes ◽  
Antifungal Antibiotic ◽  
Type Iv ◽  
Two Component

ABSTRACT Lysobacter enzymogenes is a ubiquitous soil gammaproteobacterium that produces a broad-spectrum antifungal antibiotic, known as heat-stable antifungal factor (HSAF). To increase HSAF production for use against fungal crop diseases, it is important to understand how HSAF synthesis is regulated. To gain insights into transcriptional regulation of the HSAF synthesis gene cluster, we generated a library with deletion mutations in the genes predicted to encode response regulators of the two-component signaling systems in L. enzymogenes strain OH11. By quantifying HSAF production levels in the 45 constructed mutants, we identified two strains that produced significantly smaller amounts of HSAF. One of the mutations affected a gene encoding a conserved bacterial response regulator, PilR, which is commonly associated with type IV pilus synthesis. We determined that L. enzymogenes PilR regulates pilus synthesis and twitching motility via a traditional pathway, by binding to the pilA promoter and upregulating pilA expression. Regulation of HSAF production by PilR was found to be independent of pilus formation. We discovered that the pilR mutant contained significantly higher intracellular levels of the second messenger cyclic di-GMP (c-di-GMP) and that this was the inhibitory signal for HSAF production. Therefore, the type IV pilus regulator PilR in L. enzymogenes activates twitching motility while downregulating antibiotic HSAF production by increasing intracellular c-di-GMP levels. This study identifies a new role of a common pilus regulator in proteobacteria and provides guidance for increasing antifungal antibiotic production in L. enzymogenes. IMPORTANCE PilR is a widespread response regulator of the two-component system known for regulating type IV pilus synthesis in proteobacteria. Here we report that, in the soil bacterium Lysobacter enzymogenes, PilR regulates pilus synthesis and twitching motility, as expected. Unexpectedly, PilR was also found to control intracellular levels of the second messenger c-di-GMP, which in turn inhibits production of the antifungal antibiotic HSAF. The coordinated production of type IV pili and antifungal antibiotics has not been observed previously.

scholarly journals FimX, a Multidomain Protein Connecting EnvironmentalSignals to Twitching Motility in Pseudomonasaeruginosa

2003 ◽  
Vol 185 (24) ◽  
pp. 7068-7076 ◽  
Author(s):  
Bixing Huang ◽  
Cynthia B. Whitchurch ◽  
John S. Mattick
Keyword(s):  
Fluorescent Protein ◽  
Response Regulator ◽  
Type Iv Pili ◽  
Environmental Cues ◽  
Twitching Motility ◽  
Wild Type ◽  
Protein Fusion ◽  
Type Iv ◽  
Low Levels ◽  
Signal Transduction Proteins

ABSTRACT Twitching motility is a form of surface translocation mediated by the extension, tethering, and retraction of type IV pili. Three independent Tn5-B21 mutations of Pseudomonas aeruginosa with reduced twitching motility were identified in a new locus which encodes a predicted protein of unknown function annotated PA4959 in the P. aeruginosa genome sequence. Complementation of these mutants with the wild-type PA4959 gene, which we designated fimX, restored normal twitching motility. fimX mutants were found to express normal levels of pilin and remained sensitive to pilus-specific bacteriophages, but they exhibited very low levels of surface pili, suggesting that normal pilus function was impaired. The fimX gene product has a molecular weight of 76,000 and contains four predicted domains that are commonly found in signal transduction proteins: a putative response regulator (CheY-like) domain, a PAS-PAC domain (commonly involved in environmental sensing), and DUF1 (or GGDEF) and DUF2 (or EAL) domains, which are thought to be involved in cyclic di-GMP metabolism. Red fluorescent protein fusion experiments showed that FimX is located at one pole of the cell via sequences adjacent to its CheY-like domain. Twitching motility in fimX mutants was found to respond relatively normally to a range of environmental factors but could not be stimulated by tryptone and mucin. These data suggest that fimX is involved in the regulation of twitching motility in response to environmental cues.

scholarly journals Three PilZ domain proteins, PlpA, PixA and PixB, have distinct functions in regulation of motility and development in Myxococcus xanthus

2021 ◽  
Author(s):  
Sofya Kuzmich ◽  
Dorota Skotnicka ◽  
Dobromir Szadkowski ◽  
Philipp Klos ◽  
Maria Perez-Burgos ◽  
...  
Keyword(s):  
Response Regulator ◽  
Myxococcus Xanthus ◽  
Type Iv Pili ◽  
Gliding Motility ◽  
Chemosensory System ◽  
Developmental Program ◽  
Type Iv ◽  
Genes Encoding ◽  
Acetyltransferase Domain

In bacteria, the nucleotide-based second messenger bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) binds to effectors to generate outputs in response to changes in the environment. In Myxococcus xanthus, c-di-GMP regulates type IV pili-dependent motility and the starvation-induced developmental program that results in the formation of spore-filled fruiting bodies; however, little is known about the effectors that bind c-di-GMP. Here, we systematically inactivated all 24 genes encoding PilZ domain-containing proteins, which are among the most common c-di-GMP receptors. We confirm that PlpA, a stand-alone PilZ-domain protein, is specifically important for motility and that Pkn1, which is composed of a Ser/Thr domain and a PilZ domain, is specifically important for development. Moreover, we identify two PilZ-domain proteins that have distinct functions in regulating motility and development. PixB, which is composed of two PilZ domains and an acetyltransferase domain, binds c-di-GMP in vitro and regulates type IV pili-dependent and gliding motility upstream of the Frz chemosensory system as well as development. The acetyltransferase domain is required and sufficient for function during growth while all three domains and c-di-GMP binding are essential for PixB function during development. PixA is a response regulator composed of a PilZ domain and a receiver domain, binds c-di-GMP in vitro, and regulates motility downstream of the Frz chemosensory system by setting up the polarity of the two motility systems. Our results support a model whereby the three proteins PlpA, PixA and PixB act in parallel pathways and have distinct functions to regulation of motility.

scholarly journals Suppressor mutations reveal an NtrC-like response regulator, NmpR, for modulation of Type-IV Pili-dependent motility in Myxococcus xanthus

PLoS Genetics ◽  
2018 ◽  
Vol 14 (10) ◽  
pp. e1007714
Author(s):  
Daniel J. Bretl ◽  
Kayla M. Ladd ◽  
Samantha N. Atkinson ◽  
Susanne Müller ◽  
John R. Kirby
Keyword(s):  
Response Regulator ◽  
Myxococcus Xanthus ◽  
Type Iv Pili ◽  
Type Iv ◽  
Suppressor Mutations

scholarly journals Aztreonam Lysine Increases the Activity of Phages E79 and phiKZ against Pseudomonas aeruginosa PA01

2021 ◽  
Vol 9 (1) ◽  
pp. 152
Author(s):  
Carly M. Davis ◽  
Jaclyn G. McCutcheon ◽  
Jonathan J. Dennis
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Morphological Changes ◽  
Burst Size ◽  
Type Iv Pili ◽  
Biofilm Growth ◽  
Promising Alternative ◽  
Type Iv ◽  
Alternative Treatment Option ◽  
One Step ◽  
Step Growth

Pseudomonas aeruginosa is a pernicious bacterial pathogen that is difficult to treat because of high levels of antibiotic resistance. A promising alternative treatment option for such bacteria is the application of bacteriophages; the correct combination of phages plus antibiotics can produce synergistic inhibitory effects. In this study, we describe morphological changes induced by sub-MIC levels of the antibiotic aztreonam lysine (AzLys) on P. aeruginosa PA01, which may in part explain the observed phage–antibiotic synergy (PAS). One-step growth curves for phage E79 showed increased adsorption rates, decreased infection latency, accelerated time to lysis and a minor reduction in burst size. Phage E79 plus AzLys PAS was also able to significantly reduce P. aeruginosa biofilm growth over 3-fold as compared to phage treatment alone. Sub-inhibitory AzLys-induced filamentation of P. aeruginosa cells resulted in loss of twitching motility and a reduction in swimming motility, likely due to a reduction in the number of polar Type IV pili and flagella, respectively, on the filamented cell surfaces. Phage phiKZ, which uses Type IV pili as a receptor, did not exhibit increased activity with AzLys at lower sub-inhibitory levels, but still produced phage–antibiotic synergistic killing with sub-inhibitory AzLys. A one-step growth curve indicates that phiKZ in the presence of AzLys also exhibits a decreased infection latency and moderately undergoes accelerated time to lysis. In contrast to prior PAS studies demonstrating that phages undergo delayed time to lysis with cell filamentation, these PAS results show that phages undergo accelerated time to lysis, which therefore suggests that PAS is dependent upon multiple factors, including the type of phages and antibiotics used, and the bacterial host being tested.

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